Friedri ch muwziwger



Jan. 5 1926.

. F. MUNZINGER BOILER WATER LEVEL CONTROL .Driginal Filed June 19, 1923 Patented Jan. 5, 1926,

UNETE stares ea'ranrorrres.

BOILER WATER-LEVEL CONTROL.

Original application filed June 19, 1923, Serial 11 0. 846.431. Divided and this application filed September 11, 1925. Serial 1%.,55331.

To all whom it may concern:

Be it known that I, FRIEDRICH MUN- ZINGER, a citizen of the German Republic, residing at Berlin, Germany, have invented certain new and useful Improvements in Boiler VatenLevel Controls, of which the following is a specification.

The present application is a division 01' my copending application, Ser. No. 646,431, filed June 19, 1923.

My invention relates to the control of feed water supply to a steam boiler, and aims to provide a novel feed water regulator, which isresponsive both to changes in water level and to changes in boiler pressure, the same being preferably so constructed and arranged that upon a sudden increase of load, the supply of feed water to the boiler will be diminished or entirely out OE, and when increase of heat supply takes place in order to meet the increased demand for steam, and the steam pressure rises as a result of the added heat, the water level is raised, so that when conditions are such that the loadand supply of heat may be said to be in equilibrium, so that a predetermined pressure of steam is obtained, the water level is within a certain range, which is independent of the steam demand, and'only when the demand increases faster than the heat supply, or decreases faster than "the heat supply, the Water level, or rather the controlling range of water level is moved upwardly or downwardly to accumulate hernia and to utilize accumulating capacity of the boiler water space.

My invention further consists in establishing a range of control at all times by boiler pressure, and, within that range controlling the supply of feed water in response to changes in water level.

Further objects and the advantages of my invention will be apparent as the description proceeds, which is to be taken in conjunction with the accompanying drawing, which shows one form of my invention.

Referring more particularly to the accompanying drawing, a boiler 10 in which the water level is to be controlled is supplied with feed water through a conduit 11, which is controlled by a valve 12. Closing and opening of the valve 12 is effected by rotation of an arm 13 having a weight 14 on the same. Attached to the movable end sot the arm is a flexible connection 15, which quently at a certain position of float 16,

valve 12 is fully closed; at a certain lower level 22 valve 12 is fully opened. Levels 21 and 22 determine the range of control of float 16 within which range the height of water and the consequent position of float 16 determines the amount of opening of valve 12. Pulley 18 is movable to lengthen or shorten the effective length of flexible member 15 by a mechanism 26 responsive to static pressure in the boiler acting through tube 23, and comprising a piston 24, one side of which is acted upon by steam pressure transmittedthrough tube 23, and the other side of which is acted upon by a spring 25. Increase of steam pressure in theboiler decreases the effective length of flexible member 15. Decrease of steam pressure increases the effective length of flexible member 15. This static pressure responsive mechanism 26 thus raises the range 2122 within which the float controls movement of valve 12 upon rise of static pressure and conversely lowers the range 2122 upon decrease of static pressure.

The operation of the above described apparatus is as follows: Assume that, with the position of parts as shown in the drawing, that there is an increase of load on the boiler plant. Since the effect of a change in the supply of heat lags behind a change in load, the steam pressure in the boiler will fall. The force of spring 25 then overcomes the steam pressure acting on piston 24 and moves the same to the right, whereby pulley 18 is also moved to the right. The first effect of this action is a downward movement of the left hand end of arm 13 as shown, and a partial or entire closing of valve 12. The evaporation in the boiler causes, however, a more or less immediate drop of water level, as a result of which, float 16 becomes lowered and pulls the fleX- ible member 15, so that valve 12 is opener].

to increase the supply of feed water. The control of the float will now, however, be at a lower range than previously, and this lower range of float control will be maintained so long as the pressure remains at its decreased value. However, as soon as suflicient heat is supplied to the boiler to return the pressure to normal, piston 24 is moved to the left as shown, and valve 12 is opened, ihus causing the float to rise to a level such that the supply of feed water corresponds in amount to the steam evaporation, and the float has a new range of control. This action will take place even though the load remains at increased value. It will thus be seen that the static pressure responsive device 26 establishes the range of control of the float, and within that range the control is effected by water level. It is also obvious that with my control which, in normal operation, that is when the withdrawal of heat in the form of steam and the supply of heat in the form of fuel is in equilibrium, is independent of load conditions, and has the ad vantage over a load responsive control, that it does not run a lower water level continually while there is an increased load, but after having utilized the accumulating capacity of the water space of the boiler and prevented the ill effects of introduction of a great amount of cold water, as is done by many known types of regulators, it permits the return of the water level to its normal value, thus obviating the danger of too low water level and giving other advantages de sired in practice.

While I have described one form of my invention, it is evident that other forms are possible, and that many variations in structure and arrangement of parts fall within the scope of my invention.

Obviously, other known water level. refsiponsive means may be used in place of the oat.

Vhat I claim is:

1. The method of controlling the water level in a steam boiler which consists in establishing a range of control. at all times by boiler pressure, and, within that range, controlling the supply of feed water in response to changes in water level. n

2. Boiler feed water apparatus comprising a feed conduit, means to control flow through said conduit, water level responsive means, a flexible connection between the wa ter level responsive means and the first mentioned means and means responsive to boiler pressure to alter the effective length of said flexible connection.

3. Boiler feed water apparatus comprising a feed conduit, means to control flow through said conduit, a float, a flexible connection between the float and said means, and means responsive to boiler pressure to alter the effective length of said flexible connection.

4i. Boiler feed water apparatus comprising a feed conduit, means to control flow through said conduit, water level responsive means to control said means, the last mentioned means controlling the valve to maintain the water level within a certain range at a given pressure and pressure responsive means to alter the said range by raising the range upon increase of pressure and lowering the range on decrease of pressure.

The method of controlling the water level. in a steam boiler which comprises regulating the supply of feed water in response to variations in water level within a given range of water levels, raising said range up on increase of static boiler pressure and lowering said range upon decrease of static boiler pressure.

In testimony whereof I aflix my signature.

FRIEDRICH MUNZINGER. 

